Direct current electric motor

ABSTRACT

A direct current electric motor is described, which substantially comprises a permanent magnet having a plurality of N-magnetic poles and a plurality of S-magnetic poles, the N and S-magnetic poles being alternately arranged adjacent to each other, each defining a magnetic range of its own; phase coil means including a first phase coil and a second phase coil, each being composed of a plurality of groups of conductors, the conductors being extended substantially in parallel with each other, the first and second coils being displaced by a half range of a single magnetic pole of the permanent magnet, such that each group of conductors of the first phase coil and each group of conductors of the second phase coil may be alternately disposed adjacent to each other, one being disposed in one half of the magnetic range and the other being disposed in the other half thereof; and magnetism detector means including a first magnetism detector and a second magnetism detector, the first magnetism detector being connected to an end of the first phase coil and the second magnetism detector being connected to an end of the second phase coil, the first and second magnetism detectors and the first and second phase coils forming an armature to be positioned opposite to the permanent magnet movable with respect to the armature with a predetermined amount of air gap provided therebetween.

BACKGROUND OF THE INVENTION

The invention relates to a direct current electric motor, and moreparticularly relates to an arrangement of a permanent magnet and anarmature of the motor in which the permanent magnet has a plurality ofN-magnetic poles and a plurality of S-magnetic poles, each pole defininga magnetic range of its own and the armature is composed of a firstphase coil and a second phase coil each including a plurality of groupsof conductors, the conductors in each group being extended substantiallyin prallel with each other, instead of being bundled together, eachgroup of conductors of the first phase coil and each group of conductorsof the second phase coil being alternately arranged adjacent to eachother, one being disposed in one half of the magnetic range of thepermanent magnet and the other being disposed in the other half of themagnetic range, so as to produce a constant torque in each half of themagnetic range. In this connection, the conductors of the first andsecond phase coils are wholly utilized to produce a constant torque ineach half of the magnetic range for smoothly driving the motor with acomparatively high voltage and a small amount of double phase full wavecurrent with a high torque and with a remarkably reduced consumption ofelectric power.

So far the coplanar opposed-type slotless motor using a stator coilarrangement 3 as shown in FIG. 13 has been generally employed to drivethe magnetic tape in the acoustic and/or reflection apparatuses and alsoto drive the floppy disc in the various data processing apparatuses.Such a stator coil arrangement 3 has a number of first and second shuntcoils 1,2 arranged in a common plane, the coils being generally less innumber than the number of the magnetic poles provided on a permanentmagnet, and moreover comparatively large spaces 4 are provided betweenthe coils. In this case, if the number of coils is increased, the layersof coils are increased and accordingly the thickness is increased in theaxial direction. As the result, the air gap is increased between theiron base plate 5 and the permanent magnet, thus reducing the density ofmagnetic flux to deteriorate the torque effect. Therefore in order toobtain a desired output in such a stator coil arrangement 3, it isrequired to increase the torque produced by each of the coils 1 and 2.This is generally attained by using a considerably thick wire as theconductors C, so that a considerable amount of current may flow throughthe conductors. However this will inevitably result in the dimensionalenlargement of the motor and in the increase of power consumption. Sucha motor has never been usable in the apparatus such as a portable videorecorder operated by the dry element cells.

In order to overcome the defects and disadvantages of the stator coilarrangement 3 as shown in FIG. 13, there has been proposed another typeof stator coil arrangement 8 as shown in FIG. 14. This is so called aflat and overlapped type of zigzag coil arrangement, in which a pair ofzigzag coils 6,6 are arranged in combination as shown, each beingcomposed of a group of effective conductors 6a which are alternatelydisposed as being overlapped with each other. This structure willactually prevent the increase of air gap provided between a permanentmagnet and an iron plate of the magnetic circuit of the stator andrealize a high density of magnetic flux as introduced in a publicationunder the title "DC Servo Motor For Mechatronics" the 3rd edition, pages112-125 issued by Sogo Denshi (Electronics) Publisher, and a publicationunder the title "National Technical Report" the 26th volume, 5th issue,pages 774-782.

However this zigzag type of coil arrangement 8 still includes variousdefects to be further improved. Namely since the conductors C of eachzigzag coil 6 are bundled together, the effective portion 6a ofconductors for actually producing a torque is smaller with respect tothe magnetic range defined by each magnetic pole of the permanentmagnet, and on the other hand the portions 6b,6c of conductorsineffective to produce the torque are comparatively larger, andtherefore the torque generation rate is lower and also the torquevariation is higher resulting in the increase of power consumption.Further in case of the differential double phase full wave drive, themotor will have vibrations generated in the axial direction which maydeteriorate the N and S-magnetic effects. Further in case of the sinewave drive in which the wave form of Hall generators to be employed willdirectly become the wave form for driving the motor, the disorder of theHall generators, such as the variations in the DC offset and sensitivityof the Hall generators will considerably deteriorate the wow flutter. Itis required to make a precise adjustment of the DC offset andsensitivity of the Hall generators in order to attain a normalperformnce, as stated in the publication "National Technical Report" asmentioned above. In order to solve such a problem, the publicationteaches to employ a specific, however, complex system introduced as a"current distribution double phase full wave drive system" whichrequires so many electronic circuits including so many elements.

OBJECTS AND SUMMARY OF THE INVENTION

The invention has been provided to eliminate the defects anddisadvantages of the prior art. It is therefore a primary object of theinvention to provide a permanent magnet having a plurality of N-magneticpoles and a plurality of S-magnetic poles, each defining a magneticrange of its own and first and second phase coils each composed of aplurality of groups of conductors, the conductors in each group beingextended substantially in parallel with each other, each group ofconductors of the first phase coil and each group of the second phasecoil being alternately arranged adjacent to each other, one beingdisposed in one half of the magnetic range and the other being disposedin the other half thereof, so as to produce a constant torque in eachhalf of the magnetic range for smoothly driving the motor. It is anotherobject of the invention to provide a maximum portion of each group ofconductors which may be effective to produce a torque and a minimumportion of each group of conductors which may be ineffective to producea torque, so as to drive the motor with a comparatively high voltage anda small amount of current by way of an easily obtained differentialdouble phase full wave drive system. It is another object of theinvention thus to provide a small sized direct current electric motordriven smoothly with a high torque with a remarkably reduced consumptionof electric power. It is another object of the invention to arrange thefirst and second phase coils in which the groups of conductors of bothcoils are alternately disposed as displaced by the electric angle 90° soas to make the armature flat to the maximum degree to thereby provide aminimum amount of air gap between the permanent magnet and amagnetizable base to which the armature is secured; It is another objectof the invention to secure the armature to the magnetizable base with aneddy-current suppressor plate being inserted therebetween, theeddy-current suppressor plate being made of a magnetizable materialhaving a comparatively high intrinsic resistance, so as to prevent theeddy-current which may otherwise be produced in the groups of conductorsof the first and second phase coils and simultaneously to highten atorque and reduce the power consumption. It is another object of theinvention to form the eddy-current suppressor plate by coaxially windingup or laminating a silicon steel lamination providing a radiallyextended lamination layer which may be suitable for a flat-type ofdirect current motor effectively driven without having the undesirededdy-current which may otherwise be produced in the armature; It isstill another object of the invention to provide the arrangement of thepermanent magnet, the armature and/or the eddy-current suppressor plate,which may be used in the direct current electric motor of flat type,inner rotor type or linear type.

In short, the invention comprises a permanent magnet having a pluralityof N-magnetic poles and a plurality of S-magnetic poles arrangedthereon, the N and S-magnetic poles being alternately arranged adjacentto each other, each defining a magnetic range of its own; phase coilmeans including a first phase coil and a second phase coil, each beingcomposed of a plurality of groups of conductors, the conductors in eachgroup being extended substantially in parallel with each other, thefirst and second phase coils being displaced by a half range of a singlemagnetic pole of the permanent magnet, such that each group ofconductors of the first phase coil and each group of conductors of thesecond phase coil may be alternately disposed adjacent to each other,one being disposed in one half of the magnetic range and the other beingdisposed in the other half thereof; and magnetism detector meansincluding a first magnetism detector and a second magnetism detector,the first magnetism detector being connected to an end of the firstphase coil and the second magnetism detector being connected to a end ofthe second phase coil, wherein the first and second magnetism detectorsand the first and second phase coils form an armature to be positionedopposite to the permanent magnet with a predetermined amount of air gapprovided therebetween.

Another aspect of the invention further comprises a base of amagnetizable material for securing thereto the armature and aneddy-current suppressor plate of a magnetizable material having acomparatively high intrinsic resistance, the eddy-current suppressorplate being inserted between the armature and the base.

Another aspect of the invention includes the eddy-current suppressorplate which may be formed with a lamination of a magnetizable materialsuch as a silicon steel, the lamination being coaxially wound up orlaminated to provide a radially extended lamination layer.

Another aspect of the invention includes the permanent magnet which maybe formed into a cylinder, the eddy-current suppressor plate which maybe formed into a cylinder and arranged as coaxial with the permanentmagnet with a predetermined amount of air gap provided therebetween andthe base which may be formed into a cylinder for coaxially securingthereto the armature by way of the cylindrical eddy-current suppressorplate being inserted therebetween.

Another aspect of the invention includes the permanent magnet which maybe made linear and the armature which may be made linear and arrangedopposite to the linear permanent magnet with a predetermined amount ofair gap provided therebetween, the armature being secured to the base ofa magnetizable material by way of the eddy-current suppressor platebeing inserted therebetween.

Other features and advantages of the invention will be apparent from thefollowing description of preferred embodiments in reference to theattached drawings.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 represents explanatory plan views of a permanent magnet and anarmature arranged side by side for a direct current electric motor;

FIG. 2 represents a first motor embodiment of the invention shown invertical section;

FIG. 2A represents a perspective view of a ring-shaped eddy-currentsuppressor plate which is made of a lamination coaxially wound up;

FIG. 2B represents a perspective view of another type of ring-shapededdy-current suppressor plate made of laminations coaxially laminated;

FIG. 2C represents a perspective view of a hexagonal eddy-currentsuppressor plate made of a lamination coaxially wound up;

FIG. 2D represents a perspective view of another type of hexagonaleddy-current suppressor plate made of laminations coaxially laminated;

FIG. 3 represents a double phase full wave current flowing through thearmature of the invention;

FIGS. 4 through 7 represent the explanatory views showing a series ofrotational operations of the first embodiment of the invention;

FIG. 8 represents a second motor embodiment of the invention shown invertical section;

FIG. 9 represents an exploded perspective view of the second motorembodiment;

FIG. 10 represents a partly enlarged perspective view of an armature ofthe second motor embodiment;

FIG. 11 represents explanatory plan views of a permanent magnet and anarmature of the third motor embodiment of the invention;

FIG. 12 represents a front elevational view of the third motorembodiment;

FIG. 13 represents a plan view of a shunt coil arrangement of a priorart; and

FIG. 14 represents a plan view of a zigzag coil arrangement of anotherprior art.

DETAILED DESCRIPTION OF THE INVENTION

In reference to FIG. 1, the components 9 of a direct current electricmotor of the invention are composed of a permanent magnet 10, a firstphase coil 11, a second phase coil 12, a first magnetism detector H₁,and a second magnetism detector H₂. The permanent magnet 10 is ringshaped with a center axis O and has a predetermined number of N-magneticpoles N and a predetermined number of S-magnetic poles S providedtherearound, both of the N and S-magnetic poles being alternatelyarranged adjacent to each other.

The first phase coil 11 is composed of a plurality of groups 13 ofconductors C, the conductors of each group being extended alonggenerally radial lines adjacent with each other in a half range of eachdivision defined by each of N and S-magnetic poles 10_(n), 10_(s) asillustrated with solid lines. More precisely, the conductors C of eachgroup are disposed within the range of electric angle 90° in a manner asextended along generally radial lines adjacent with each other with apredetermined space provided therebetween without being bundledtogether. As shown, the first phase coil 11 is as a whole formed up in azigzag shape. Here it is to be noted that because the conductors C arenot bundled together as are in the conductors the conventional art,linear segments or portions 11a of the conductors C, which are effectiveto produce a torque, are substantially longer than conventional whilethe portions 11b of the conductors C, which are ineffective to producethe torque are considerably smaller than conventional. Also, as may beseen in FIG. 1, each of the linear segments 11a are spaced and radiallyoriented but more generally oriented to be transverse to the directionof relative movement between the conductors C and the permanent magnet10.

The second phase coil 12 is formed in the same manner as the first phasecoil 11 and is composed of a plurality of linear segment groups 14 ofthe conductors C as illustrated by the broken lines which are formed upin a zigzag shape. Each of the conductor linear segment groups 14 islocated in the half range of a single magnetic pole 10_(n) or 10_(s) ofthe permanent magnet 10, each adjacent to the alternate one of theconductor groups 13 of the first phase coil 11.

As the first magnetism detector H₁, a Hall generator is used by way ofexample, and is secured to the end 11c of the first phase coil 11.Another Hall generator as the second magnetism detector H₂ is secured tothe end 12c of the second phase coil 12.

Thus the first phase coil 11 and the second phase coil 12 are coaxiallyarranged as being angularly displaced to each other by the half range ofa single magnetic pole 10n or 10s of the permanent magnet 10 such thatthe group 13 and 14 with the effective linear segment conductor portions11a and 12a are alternately located each adjacent to the other in eachmagnetic pole 10n or 10s all through the range of 360° the permanentmagnet 10. In this way, an extremely thin armature 16 is provided by thefirst and second phase coils 11 and 12 and the first and secondmagnetism detectors H₁ nad H₂ which are combined to each other asmentioned.

In a direct current electric motor of the invention, the armature 16 isarranged coaxially with the permanent magnet 10 with an air gap, i.e., aclearance of a predetermined distance provided therebetween.

The first and second phase coils 11 and 12 may be the windings of enamelwire wound up as shown in FIG. 1 by means of a wire winding machine, ormay be the printed coils having the copper provided thereon aselectrolyzed by means of electrolytic or non-electrolytic plating.

Further in reference to FIG. 2, a first motor embodiment of theinvention will be described with the same reference numerals being usedwith respect to the parts common to those of the components shown inFIG. 1.

A direct current electric motor 19 of flat-type of the first motorembodiment is composed of the ring shaped permanent magnet 10 having aplurality of divisions defined by N and S magnetic poles 10n, 10s whichare alternately arranged all through 360° of the magnet, and thearmature 16 composed of the first phase coil 11 having a plurality ofgroups 13 of conductors C with their individual linear segments 11aextending along generally radial lines adjacent to each other in onehalf range of each division defined by each of the N and S magneticpoles 10n, 10s of the permanent magnet 10, the second phase coil 12having a plurality of groups 14 of conductors C with their individuallinear segments 12a extending along generally radial lines adjacent toeach other in the other half range of each division defined by each ofthe N and S magnetic poles 10n,10s of the permanent magnet 10, the firstmagnetism detector H₁ and the second magnetism detector H₂, wherein thefirst and second phase coils 11, 12 are arranged in combination asangularly displaced from each other by the half range of each divisiondefined by each of the N and S magnetic poles 10n, 10s of the magnet 10,such that the groups 13,14 of the conductors C are alternately disposedas one adjacent to the other in each division defined by each of themagnetic poles 10n and 10s all through the 360° of the permanent magnet10, and the first magnetism detector H₁ is secured to the end 11c of thefirst phase coil 11 while the second magnetism detector H₂ is secured tothe end 12c of the second phase coil 12. The armature 16 is arrangedcoaxially with the permanent magnet 10 with a predetermined air gap 18provided therebetween, and is secured to a base 23 of iron by way of anintermediate eddy-current suppressor plate 20 of a magnetizable materialhaving a comparatively high intrinsic electric resistance. Theeddy-current suppressor plate 20 is employed as the intermediatelylocated element to suppress the eddy-current, which may otherwise beproduced in the coils of the armature 16 when the extremely thinarmature 16 preferably of printed coils is directly secured to the base23 of iron, and which may otherwise lower the output of the motor whileincreasing the consumed power of the motor. The eddy-current suppressorplate 20 may be a nonmagnetizable ferrite plate or may be a siliconsteel lamination coaxially wound up as shown in FIG. 2A as to suppressthe eddy-current to thereby increase the output of the motor with asmaller amount of consumed power. The eddy-current suppressor plate 20of coaxially wound up lamination has a radially extended laminationlayer. This may however be formed with the laminations coaxiallylaminated to provide the radially extended lamination layer as shown inFIG. 2B. The configuration of the eddy-current suppressor plate 20 willnot be limited to the ring-shaped one, but may be polygonal including ahexagonal one having the lamination coaxially wound up as shown in FIG.2C or having the laminations coaxially laminated as shown in FIG. 2D.

The permanent magnet 10 is secured to a rotor yoke 24 of a magnetizablematerial such as iron, which is in turn secured to a boss 26 fixedlymounted on a rotor shaft 25. The rotor shaft 25 is axially supported bya center radial bearing 29 accommodated in a cover 28 which is securedto the base 23, and is prevented from axial movement by means of athrust bearing 30. Therefore if a turntable (not shown) is connected tothe rotor shaft 25, the flat motor 19 may be used as a phonomotor.

Now in reference to FIGS. 8 through 10, a direct current electric motor29 of inner-rotor type will be described as a second motor embodiment ofthe invention. The direct current electric motor 29 of inner-rotor typeis composed of a permanent magnet 30 in a form of cylinder havingN-magnetic poles N and S-magnetic poles S alternately arrangedtherearound each adjacent to the other, a first phase coil 31 in a formof cylinder having a plurality of groups 33 of conductors C extended inparallel with each other in one half range of each division defined byeach of the N and S-magnetic poles 30n, 30s of the permanent magnet 30,a second phase coil 32 in a form of cylinder having a plurality ofgroups 34 of conductors C extended in parallel with each other in theother half range of each division defined by each of the N andS-magnetic poles 30n, 30s of the permanent magnet 30, a first magnetismdetector H₁ and a second magnetism detector H₂, wherein the first andsecond phase coils 33, 34 are formed in a cylinder and arranged incombination as angularly displaced from each other by the half range ofeach division defined by each of the N and S-magnetic poles 30n, 30s ofthe permanent magnet 30, such that the conductor groups 33 and 34 arealternately disposed as one adjacent to the other in each divisiondefined by each of the magnetic poles 30n and 30s of the permanentmagnet 30, and the first magnetism detector H₁ is secured to the end 31cof the first phase coil 31 and the second magnetism detector H₂ issecured to the end 32c of the second phase coil 32. Thus the first andsecond phase coils 31, 32 and the first and second magnetism detectorsH₁, H₂ form a cylindrical armature 36 which is arranged around thecylindrical permanent magnet 30 having a rotor shaft 35 with apredetermined air gap 38 provided therebetween. The armature 36 issecured to the inner periphery of a cylindrical case 43 of amagnetizable material such as an iron by way of an intermediateeddy-current suppressor cylinder 40 which made of a material having acomparatively high intrinsic electric resistance. The cylindrical case43 is composed of a case body 43a and a cover 43b having a centralbearing 39 for rotatably supporting one end of the rotor shaft 35 of thecylindrical permanent magnet 30. The eddy-current suppressor cylinder 40may be a lamination of silicon steel plates or a plurality ofnonmagnetizable ferrite plates as shown.

In reference to FIGS. 11 and 12 showing a direct current linear electricmotor 49, respectively of the components of a direct current linearelectric motor and third motor embodiment of the invention, the linearmotor 49 is composed of a linear permanent magnet 50 having a pluralityof N and S magnetic poles 50n, 50s linearly and alternately arranged allthrough the length of the magnet, a plurality of groups 51 of firstphase conductors C extended in parallel with each other in one halfrange of each division defined by each of the N and S magnetic poles50n, 50s of the magnet 50, a plurality of groups 52 of second phaseconductors C extended in parallel with each other in the other halfrange of each division defined by each of the N and S magnetic poles50n,50s of the magnet, the first magnetism detector H₁ an the secondmagnetism detector H₂, wherein the first and second phase conductors Care set in combination as linearly displaced from each other by the halfrange of each division defined by each of N and S magnetic poles 50n,50s of the magnet 50, such that the first and second phase conductors Care alternately disposed as one adjacent to the other in each divisiondefined by each of the N and S magnetic poles 50n, 50s of the magnet 50,and the first magnetism detector H₁ is secured to the end 5lc of thegroups 51 of the first phase conductors and the second magnetismdetector H₂ is secured to the end 52c of the groups 52 of the secondphase conductors C. Thus the groups 51, 52 of the first and second phaseconductors C and the first and second magnetism detectors form a lineararmature 60 which is arranged opposite to the reciprocatingly movablelinear permanent magnet 50 with a predetermined air gap 48 providedtherebetween while the linear armature 60 as an eddy-current suppressorplate 70 secured thereto which is made of a material having acomparatively high intrinsic electric resistance.

Now in reference to FIGS. 1 through 7, the direct current electric motor19 of the first embodiment is operated as follows: The permanent magnet10 having the center axis O and arranged coaxially with the armature 16with a predetermined air gap provided therebetween is to be assumed torotate in the counterlockwise direction in FIGS. 2 and 4. A differentialdouble phase full wave current as shown in FIG. 3 is applied to thefirst and second phase coils 11, 12. As shown in FIG. 4, when a juncture10a between the S-magnetic pole S and the N-magnetic pole N of thepermanent magnet 10 coincides with the electric angle 0°, the firstmagnetism detector H₁ secured to the end 11c of the first phase coil 11detects the change of magnetism from the S-magnetic pole to theN-magnetic pole and produces a signal. Then the current flows throughthe groups 13 of conductors C to produce a driving force, and thepermanent magnet 10 is rotated in the counterclockwise direction asindicated by an arrow mark A. As shown in FIG. 3, a pulse shape positivefull wave current flows through the first phase coil 11 within the rangebetween the electric angles 0° and 90°. As shown in FIG. 5, when thepermanent magnet 10 rotates through the electric angle 90° where thejuncture 10a etween the N and S-magnetic pole comes to the secondmagnetism detector H₂, the second magnetism detector H₂ ceases to detectthe magnetism of the S-magnetic pole S and starts to detect themagnetism of the N-magnetic pole N. With this change of magnetismdetection, the flow of current through the first phase coil 11 isstopped, and then the pulse shape positive full wave current flowsthrough the second phase coil 12.

Therefore the groups 13, 14 of conductors C will have no reversed torquegenerated therein and will have a substantially even torque in view ofthe arrangement of such groups 13, 14 of conductors though it may beadmitted that the magnetic flux is stronger at the center of eachmagnetic pole and is weaker at both ends thereof.

Further when the permanent magnet 10 rotates through the electric angle180° as shown in FIG. 6, the juncture 10a between the N and S-magneticpoles comes to coincide with the first magnetism detector H₁, the firstmagnetism detector H₁ ceases to detect the magnetism of the N-magneticpole and starts to detect the magnetism of the S-magnetic pole. Withthis change of magnetic detection, the flow of current through thesecond phase coil 12 is stopped, and then the pulse shape negative fullwave current flows through the first phase coil 11 as shown in FIG. 3.Thus the permanent magnet 10 continuous to rotate in the same direction.Further as shown in FIG. 7, when the permanent magnet 10 rotates throughthe electric angle 270°, the second magnetism detector H₂ detects themagnetism of the S-magnetic pole instead of the N-magnetic pole, andaccordingly the current is stopped to flow through the first phase coil11 and the pulse shape negative full wave current flows through thesecond phase coil 12. Thus the permanent magnet 10 continuous to rotateconstantly in the same direction.

As is apparent from the foregoing description, the first andsecond-magnetism detectors H₁, H₂ alternately detect the N andS-magnetic poles N and S to alternately flow the differential positiveand negative double phase full wave current through the first and secondphase coils 11, 12, to thereby successively produce a driving force inthe conductors 11a, 12a of the first and second phase coils 11, 12. Inthis way, the direct current electric motor 9 of the invention willsmoothly rotate with a remarkably strong torque. Moreover as shown, theineffective conductor portions 11b, 12b are designed to be minimum incontrast to the effective conductor parts 11a, 12a so as to highten theefficiency of the first and second phase coils 11, 12, i.e., to obtainthe maximum amount of rotational torque. Further according to thisembodiment, the effective conductor parts 11a, 12a are successivelyoperated to constantly and stabilizingly rotate the motor 19 with aminimum consumption of electric power.

In reference to FIG. 2 the first and second phase coils 11, 12 of thearmature 16 may be made up as the printed coils so as to form thearmature 16 extremely thin. If the armature 16 is directly attached tothe base 23, the eddy-current will be produced in the coils 11, 12,resulting in remarkably lowering the output of the motor 19 whileincreasing the consumption of electric power. The eddy-current may beprevented from being produced by providing the eddy-current suppressorplate 20 between the armature 16 and the base 23. The eddy-currentsuppressor plate 20 may be a nonmagnetizable ferrite plate or may be asilicon steel lamination coaxially wound up or coaxially laminated toprovide a radially extended lamination layer which will be effective tosuppress the eddy-current which may otherwise be produced in the firstand second phase coils 11, 12 of the armature 16. As the result, thedriving force of the armature 16 is increased while the consumed powerof the motor is decreased, in contrast to the case of directly attachingthe armature 16 to a base of synthetic resin. The effect of theeddy-current suppressor plate 20 as mentioned above has been actuallyconfirmed in the experiments as a specific feature of such a flat-typedirect current electric motor 19.

In reference to FIGS. 8 through 10 showing the second motor embodimentof the invention, the direct current electric motor 29 of inner-rotortype is same in principle with the first and second embodiments of theinvention. According to this embodiment, the armature 36 in the form ofcylinder is composed of the first and second phase coils 31, 32 havingthe first and second magnetism detectors H₁, H₂ respectively, which arealternately operated to continuously flow the double phase full wavecurrent through the first and second phase coils 31, 32 of the armature36, to thereby rotate the cylindrical permanent magnet 30 in onedirection while the eddy-current suppressor cylinder 40 is operated tosuppress the eddy-current which may otherwise be produced in thearmature 36. The cylindrical permanent magnet 30 is rotated with thecenter shaft 35 journalled in the bearing 39 in the case 48. In thisembodiment, the cylindrical eddy-current suppressor element 40 isprovided to suppress the eddy-current which may otherwise be produced inthe armature 36. Therefore an extremely strong torque may be obtainedeven if the armature 36 is attached to the case 43 of a magnetizablematerial such as iron for a magnetic circuit. Moreover the rotation ofthe motor 29 is smooth while the consumption of power is minimum.

In reference to FIGS. 11 and 12 showing the third motor embodiment ofthe invention, the linear-type direct current electric motor 49 has thelinear permanent magnet 50 and the similar armature 60 which areoperated in the same principle with the first and second embodiments ofthe invention. The double phase full wave current flows through thefirst groups of conductors 51 and the second groups of conductors 52 inthe manner as shown in FIG. 3 by the first and second magnetismdetectors H₁, H₂ which alternately detect the magnetism of the N andS-magnetic poles 50n, 50s of the permanent magnet 50. The linearpermanent magnet 50 may be linearly moved in the direction as indicatedby the arrow mark B or D in dependence upon the control of the lineartype direct current electric motor 49. In this case, as the armature 60is secured to the eddy-current suppressor plate 70, the eddy-currentwill not be produced in the armature 60 even if the latter is attachedto a magnetizable base (not shown) such as an iron base. The armature 60will produce a strong driving force with a minimum consumption of power.

Having thus set forth the nature of the invention, it will be obviousthat the invention may be varied or modified in many ways. Suchvariations or modifications will not be regarded as a departure from thespirit and scope of the invention, but will be included within the scopeof the following claims.

What is claimed is:
 1. A direct current electric motor comprising apermanent magnet having a plurality of N-magnetic poles and a pluralityof S-magnetic poles arranged thereon, said N and S-magnetic poles beingalternately arranged adjacent to each other, each defining a magneticrange of its own; phase coil means including a first phase coil and asecond phase coil, each being composed of a plurality of conductors,said conductors each having a plurality of electromagnetic forceproducing linear segments, each such linear segment being spaced from anadjacent linear segment and oriented generally transverse to thedirection of relative movement between said conductors and saidpermanent magnet, said adjacent linear segments of said conductors ofsaid first phase coil and of said second phase coil, respectively, beingarranged in groups of linear conductor segments, said first and secondphase coils being displaced by a half range in each magnetic pole ofsaid permanent magnet with each group of linear conductor segments ofsaid first phase coil and each group of linear conductor segments ofsaid second phase coil alternately disposed adjacent to each other, onebeing disposed in one half of said magnetic range and the other beingdisposed in the other half thereof; and magnetism detector meansincluding a first magnetism detector and a second magnetism detector,said first magnetism detector being connected to an end of said firstphase coil and said second magnetism detector being connected to an endof said second phase coil, and wherein said first and second magnetismdetectors and said first and second phase coils form an armature to bepositioned opposite to said permanent magnet with a predetermined amountof air gap provided therebetween.
 2. A direct current electric motor asdefined in claim 1, wherein said first and second phase coils areprinted coils.
 3. A direct current electric motor as defined in claim 1comprising a cylindrical case of magnetizable material, an eddy currentsuppressor cylinder made of magnetizable material having a comparativelyhigh intrinsic resistance, said eddy current suppressor cylinder beingsecured to said cylindrical case, said phase coil means and saiddetector means providing a cylindrical armature secured to said eddycurrent suppressor cylinder, and wherein said permanent magnet if ofcylindrical form dimensioned to provide said predetermined amount of airgap with said cylindrical armature, thereby to provide an inner-rotortype electric motor configuration.
 4. A direct current electric motor asdefined in claim 1, comprising a linear base of magnetizable material, alinear eddy current suppressor plate made of magnetizable materialhaving a comparatively high intrinsic resistance, said eddy currentsuppressor plate being secured to said base, said phase coil means andsaid detector means providing a linear armature secured to said eddycurrent suppressor plate, said permanent magnet being linear in form andmovable linearly with respect to said armature while spaced therefrom bysaid predetermined amount of air gap, thereby provide a linear electricmotor configuration.
 5. A direct current electric motor of flat typecomprising a permanent magnet having a plurality of N-magnetic poles anda plurality of S-magnetic poles being alternately arranged adjacent toeach other, each defining a magnetic range of its own; phase coil meansincluding a first phase coil and a second phase coil, each beingcomposed of a plurllity of conductors, said conductors each having aplurality of linear segments being extended along generally radial linesextending from a rotation axis of said permanent magnet with apredetermined space provided between adjacent linear segments, saidadjacent linear segments of said conductors of said first phase coil andof said second phase coil, respectively, being arranged in groups oflinear conductor segments, said first and second phase coils beingdisplaced by a half range in each magnetic pole of said permanent magnetwith each group of linear conductor segments of said first phase coiland each group of linear conductor segments of said second phase coilalternately disposed adjacent to each other, one being disposed in onehalf of said magnetic range and the other being disposed in the otherhalf thereof; and magnetism detector means including a first magnetismdetector and a second magnetism detector, said first magnetism detectorbeing connected to an end of said first phase coil and said secondmagnetism detector being connected to an end of said second phase coil,said first and second magnetism detectors and said first and secondphase coils forming an armature to be positioned opposite to saidpermanent magnet with a predetermined amount of an air gap providedtherebetween.
 6. A direct current electric motor as defined in claim 5,further comprising:an eddy-current suppressor plate for securing saidarmature thereto.
 7. A direct current electric motor as defined in claim6, wherein said eddy-current suppressor plate is made of a magnetizablematerial having a comparatively high intrinsic resistance.
 8. A directcurrent electric motor as defined in claim 6, wherein said eddy-currentsuppressor plate is made of a nonmagnetizable ferrite plate.
 9. A directcurrent electric motor as defined in claim 6, wherein said eddy-currentsuppressor plate is a lamination layer of a magnetizable materialincluding silicon steel plates.
 10. A direct current electric motor asdefined in claim 6, further comprising:a base of a magnetizable materialfor securing said eddy-current suppressor plate.
 11. A direct currentelectric motor as defined in claim 1, wherein said permanent magnet andsaid armature are made in a ring-shaped configuration.
 12. A directcurrent electric motor of flat type comprising a permanent magnet havinga plurality of N-magnetic poles and a plurality of S-magnetic polesarranged thereon, said N and S-magnetic poles being alternately arrangedadjacent to each other, each defining a magnetic range of its own; phasecoil means including a first phase coil and a second phase coil, eachbeing composed of a plurality of conductors, said conductors each havinga plurality of linear segments being extended along generally radiallines extending from a rotational axis of said permanent magnet with apredetermined space provided between adjacent linear segments, saidadjacent linear segments of said conductors of said first phase coil andof said second phase coil, respectively, being arranged in groups oflinear conductor segments, said first and second phase coils beingdisplaced by a half range in each magnetic pole of said permanent magnetwith each group of linear conductor segments of said first phase coiland each group of linear conductor segments of said second phase coilalternately disposed adjacent to each other, one being disposed in onehalf of said magnetic range and the other being disposed in the otherhalf thereof; magnetism detector means including a first magnetismdetector and a second magnetism detector, said first magnetism detectorbeing connected to an end of said first phase coil and said secondmagnetism detector being connected to an end of said second phase coil,said first and second magnetism detectors and said first and secondphase coils forming an armature to be positioned opposite to saidpermanent magnet with a predetermined amount of an air gap providedtherebetween; eddy-current suppressor means including an eddy-currentsuppressor plate for securing said armature thereto, said eddy-currentsuppressor plate being made of a magnetizable material including asilicon steel lamination coaxially wound up or laminated to provide aradially extended lamination layer; and a base of a magnetizablematerial for securing said eddy-current suppressor plate thereto.